A variety of devices make use of use of a light sensor array. Examples of these devices include medical imaging devices such as positron emissision tomography (PET) scanners. The light sensor arrays employed in PET scanners has a plurality of pixels. Each of the pixels includes one or more detection circuits that each has a resistor connected in series with an avalanche photodiode. During operation of the device, each detection circuit provides an output signal in response to the avalanche photodiode in that detection circuit receiving a photon. As a result, the output signals from the detection circuits in a pixel can be used to determine the number of photons incident on the avalanche photodiodes in the pixel.
The resistors in the detection circuits of a single device can have a wide range of resistance values. However, the output signal provided by a detection circuit is dependent on the resistor in that detection circuit. Accordingly, the variation in resistor values can cause the output signals from different detection circuits to have a wide range of values. The variation in these output signals can result in an inaccurate determination in the number of photons that are received by the photodiodes in a pixel.
As a result, there is a need for improved light sensor arrays.